The present disclosure relates to a lighting apparatus that reproduces, for example, holograms and holographic stereograms that have been created.
A hologram that reproduces a three-dimensional image can be composed of original two-dimensional images of an object viewed from different view points. A holographic stereogram is created by successively recording original images of which one object has been successively photographed for example from different view points as stripe-shaped or dot-shaped element holograms on one hologram record material.
As shown in FIG. 1, in a holographic stereogram having parallax information for example only in the lateral direction, by successively photographing an object 100 from different view points in the lateral direction, a plurality of parallax images 101a to 101e are successively obtained. The parallax images 101a to 101e are linearly focused for example on a hologram record medium 102. With reference light having a predetermined angle, the parallax images 101a to 101e are recorded on the hologram record medium 102. In other words, as shown in FIG. 2, a parallax image sequence D1 is divided in a stripe shape in the parallax direction and stripe-shaped data of different parallax images are reconstructed. By performing the so-called “slice and dice” image process, a hologram image D2 is created. An image recording apparatus successively records stripe-shaped element holograms on the hologram record medium 102, resulting in creating the hologram image D2.
In this holographic stereogram, since image information obtained by successively photographing an object from different view points in the lateral direction is successively recorded as stripe-shaped element holograms in the lateral direction, when a user views this holographic stereogram with both his or her eyes, two dimensional-images in his or her eyes slightly become different. As a result, the user feels a parallax. Thus, a three-dimensional image is reproduced.
A high quality hologram image can be viewed with light emitted in a predetermined direction from a point light source. Instead, by illuminating a hologram image with direct sunlight or a home incandescent lamp, a hologram image can be clearly viewed. However, when a hologram image is viewed outdoor on cloudy or under a fluorescent lamp, the hologram image becomes dimmed. When a hologram image is illuminated with a plurality of incandescent lamps, a plurality of images are viewed. In addition, a high quality hologram image may not be viewed depending on the positional relationship with the light source. Thus, the quality of a hologram image varies depending on various viewing conditions. To solve such a problem, a viewer that fixes the positional relationship between a light source and a hologram, namely a lighting apparatus having a light source with which a hologram image is reproduced, has been proposed. This applies to the case that a holographic stereogram composed of a plurality of element holograms is reproduced.
A lighting apparatus is preferably small in size such that it has portability that allows the apparatus to be used and placed anywhere. In addition, there is a risk of which the positional relationship between a portion at which a hologram or the like is attached and a light source deviates while the lighting apparatus is being carried. If the positional relationship deviates, a hologram image or a holographic stereogram is not reproduced in high quality. Thus, to view a hologram or a holographic stereogram in high quality, it is necessary to keep the positional relationship between the hologram and so forth and the light source such that it usually satisfies an optimum viewing condition.
As such a lighting apparatus, a lighting apparatus 1 as shown in FIG. 3 is described in Japanese Patent Application Laid-Open No. 2003-229004.
The lighting apparatus 1 is composed of a base section 2, an arm section 3 disposed on the base section 2, and a lamp section 4 disposed at an end of the arm section 3. The arm section 3 is composed of two elastic rods 3a and 3b that are horizontally held by a connection portion 6. The lamp section 4 has a light source 4a and a shade 4b that covers the light source 4a. Disposed on the connection portion 6 is a clip 7. The clip 7 holds a hologram card 8. The hologram card 8 is composed of a base material 8a and a holographic stereogram 8b adhered on one surface of the base material 8a. 
Such a lighting apparatus has the base section 2 and the lamp section 4 is bulky. Thus, it is difficult to say that the lighting apparatus has excellent portability. In addition, Japanese Patent Application Laid-Open No. 2003-229004 describes a lighting apparatus having a pen-shaped arm section diagonally disposed on the base section. However, since this lighting apparatus has the pen-shaped arm section and a light source section protrudes from the pen-shaped arm section. Thus, it is difficult to say that the lighting apparatus has excellent portability.
In view of the foregoing, it would be desirable to provide a lighting apparatus used to view holograms with excellent portability because of use of a non-protruded light source section and omission of a base section unlike Japanese Patent Application Laid-Open No. 2003-229004.